List of Glossary of Physics Terms and Description

Term	Description
Acceleration	It is the rate of change of the velocity of a moving body.
Acoustics	It is the experimental and theoretical science of sound and its transmission.
Alternative energy	It is the energy from sources that are renewable and ecological safe, as opposed to sources that are non-renewable with toxic by-product, such as coal, oil or gas and uranium.
Altimeter	It is an instrument used in aircraft that measures altitude, or height above sea level.
Ammeter	It is a device used to measure current.
Archimedes principle	It is the law stating that an object that is totally or partly submerged in a fluid displaces a volume of fluid that weighs the same as the apparent loss in weight of the object.
Armature	It is a part of some electric machines.
Atmosphere	It is the mixture of gases that surrounds the Earth; it is prevented from escaping by the pull of the Earth’s gravity.
Atom	It is the smallest unit of matter that can take part in a chemical reaction and which cannot be broken down chemically into anything simpler.
Astrophysics	It is the study of the structure of the universe and how the objects in it behave.
Ballistics	It is the science of the movement and behaviour of missiles. Projectiles from guns, refuels and slings, bombs, rockets and so forth.
Barometer	It is the instrument that measures atmospheric pressure as indication weather.
Buoyancy	It is the effect of the upward force (upthrust) on an objective in a fluid.
Calibrate	It describes how a measuring scale is marked.
Calliper	It is a kind of measuring instrument.
Calorie	It is a unit of energy content of food.
Calorimeter	It is an apparatus for measuring heat.
Cantilever	It is a beam securely fixed at one end and hanging fee at the other hand.
Capacitor	It is a device which can store electricity.
Capillarity	It is an effect of surface tension.
Carat	It is a unit of weight for gems and precious metals. One carat is equal to 200 milligrams.
Cathode	It is a negative electrode in a cell.
Celsius	The temperature scale in which one division or degree is taken as one hundredth part of the interval between the freezing point (0⁰C) and the boiling point (100⁰C) of water at standard atmospheric pressure.
Centrifugal	It is a force away from the centre that may appear to be observed during motion in a curve.
Centripetal	It is the force that is necessary to keep an object moving in a circular path and that is directed inwards towards the centre of rotation.
Chain reaction	It is a situation where one event cause a second, this leads to a third, and so on.
Circuit breaker	It is a safety switch that automatically cuts off the current when there is an overland.
Climate	It is the long-term pattern of weather in a region.
Compass	it is an instrument which helps people to find their way from one place to another.
Cooling tower	It is part of a power station.
Coulomb	It is a unit of electric charge.
Cube	It has a solid shape, it has six square sides which are all the same size.
Curie	It is a unit of radio-activity.
Decibel	It is a unit of measurement. It measures the loudness of sound.
Diffusion	It is the movement of atoms and molecules in gases and liquids.
Digital	It is a term meaning coded as number.
Diode	It is a term part of some electric circuits.
Docking	It is the mechanical coupling of two or more spacecraft.
Dynamo	It is a simple generator, or machine for transforming mechanical energy into electrical energy.
Echo	It is a sound which is reflected.
Eclipse	it is passage of an astronomical body through the shadow of another.
Electromagnet	It is a special coil of wire.
Element	It is substance that cannot be split chemically into simpler substances.
Elastically	It is an elastic substance which obey Hooke’s law. This means that if we stretch or compress a sample, it deforms (stains) in proportion. It returns to its original state when the stress ceases.
Electron	It is one of the basic particles of matter.
Epicentre	It is a point directly above the true centre of disturbing from which the shock wavers of an earthquakes apparently radiate.
Escape speed	It is the speed of an object leaving the surface of a planet, such that it just escapes the gravitational pull.
Escape velocity	It is the minimum velocity with which an object must be projected for it to escape from the gravitational pull of a planetary body.
Fallout	These are the radio-active substance deposited upon the surface of the earth after the explosion of a nuclear weapon of mishap at a nuclear reactor.
Fibre optics	It is branch of physics dealing with the transmission of light and images though glass or plastic known as optical fibres.
Filament	It is a thin, high resistance wire as in an electric light bulb.
Filter	It is a kind of apparatus which helps to separate a mixture.
Fleming’s rules	These are memory aids for the directions of the magnetic field, current and motion in an electric generator or motor, using one’s fingers.
Fly wheel	It is a heavy wheels connected to the shaft of an engine. it maintains the smooth rotation of the shaft because of its high inertia.
Forensic science	It carries out test and searches for clues to help the police and lawyers.
Fossil fuel	Any fuel produced by the slow decay of dead things and which, therefore, is not renewable.
Free fall	It is the state in which a body is falling freely under the influence of gravity, as in free-fall parachuting.
Friction	It is the force that opposes the relative motion of two bodies in contact.
Fuse	It is a thin piece of wire, a part of an electric circuit.
Galvanometer	It is a sensitive instrument for detecting or measuring small electric currents.
Gas	It is a state of matter which has no fixed shape or volume and always fills the whole of the space in which it is contained.
Geiger counter	It is a device which measures radiation.
Generator	It is a machine that transfers kinetic energy to electricity.
Greenhouse effect	It is a phenomenon of the Earth’s atmosphere by which solar radiation, absorbed by the Earth and re-emitted from the surface, is prevented from escaping by gases, mainly carbon dioxide in the air.
Grid	It is the network by which electricity is generated and distributed over a region or country.
Hectare	It is a unit of measurement which measures area.
Hertz	It is a unit of measurement which measures the frequency of vibrations.
Hexagon	It is a flat shape which has six sides.
Horse power (hp)	It is a practical unit of power which equal to 550 foot-pound per second or 746 watts.
Hurricane	It is a powerful whirling tropical storm that measures 320 to 480 kilometres in diameter.
Hydraulics	It is the branch of physics that deals with the behaviour of liquids at rest and in motion.
Hydrometer	It is an instrument used to measures the relatives density of liquids (the density compared with that of water).
Hydrosphere	The water of the earth, ocean lakes, rivers and glaciers that cover about three-fourths of the earth’s surface.
Hygrometer	It is an instrument used to measure the amount of water vapour in the air.
Hypersonic	The sound waves which have frequencies above 500 megahertz.
Hypersonic speed	The speed of an object greater than about five times the speed of sound in the fluid through which the object is moving.
Inertia	The tendency of an object to remain in a state of rest of uniform motion until an external force is applied, as stated by Newton’s first law of motion.
Information Technology	It is a scientific subject, the study of how to collect, use, move, store and display information.
Insulation	It is the process by which the passage of electricity, heat or sound is prevented through a material.
Imaging	It is a technique by which electronics data collected by various means is converted into visual image by use of computers.
Isotopes	These are atoms of an element having the same atomic number but different atomic weights.
Jet lag	It is a state of feeling unwell and exhausted experienced by air travellers when they cross several time zones in a relatively short time.
Kinetic energy	It is a form of energy possessed by moving bodies. It is contrasted with potential energy.
Knot	It is a unit for measuring ship’s speed.
Laser	The name stands for Light Amplification by stimulated Emission of Radiation. A device able to produce an intension narrow beam of radiation.
Latent heat	It is the heat required to change the state of a substance (for example, from solid to liquid) without changing its temperature.
Latitude	It is the distance of a point on the earth’s surface from the equator.
Lighting conductor	It is a conductor of electricity installed in a structure to save it from damage.
Light-year	It is a unit of distance used in astronomy. It is defined as the distance light travels through space in one year. Light travels at 300,000 km per second.
Mach number	It is a measure of the speed of an object, specially an aircraft. If the Mach number exceeds one, the object is said to be moving at a supersonic speed.
Manometer	An instrument for measuring the pressure of liquids (including human blood pressure) or gases.
Mechanics	It is the study of movement of material bodies.
Meridian	It is an imaginary circle passing through both the poles of a celestial sphere, It is also the imaginary plane passing through the Earth’s axis.
Meteorology	It is the study of climate and weather patterns, with the aim of trying to explain, predict and change them.
Mica	It is a group of silicate minerals having layered structure.
Microscope	It is an instrument for magnification with high resolution for detail.
Mirage	It is the illusion seen in hot climate of water on the horizon, or of distant objects being enlarged.
Missile	It is guided unmanned weapon which is usually propelled by a rocked.
Moderator	It is a substance that is used to slow down neutrons emitted in a nuclear fission reaction.
Molecule	it is a group of one or more atoms bonded together, a basic participle of matter.
Momentum	It is a property dependent on the mass and velocity of a body.
Nautical mile	It is a unit of measurement, it measures distances across seas and oceans.
Nuclear fission	it is the process whereby an atomic nucleus breaks up with the emissions of several neutrons.
Nuclear reactor	It is the central component of a nuclear power station that generated nuclear energy under controlled conditions for use as a source of electrical power.
Nuclear waste	It is the radio-active and toxic by-products of the nuclear-energy and nuclear-weapons industries.
Ohm	The SI unit of electrical resistance, named after Georg Simon Ohm.
Opaque	It described a substance which does not allow light to pass through it.
Optics	It is the study of nature and properties of light.
Oscillation	One completer to and-fro movement of a vibrating object or system.
Periscope	It is an optical instrument designed for observation from a concealed position such as from a submerged submarine.
Photon	It is a particle which has been invented by scientist to explain how light behaves.
Physics	It is the branch of science concerned with the ultimate laws that govern the structure of the universe and the forms of matter and energy and their interactions.
Piston	It is a part of a machine, it is fitted inside a cylinder and moves back wards and forwards.
Plutonium	It is a radioactive metallic element (symbol Pu) of proton number 94 and relative atomic mass 239.13.
Pole	It is a region of a magnetic field where the force is strongest. Most bar magnets have two poles.
Pollution	The effect on the surface of the Earth of poisonous or harmful substances that makes life less safe or pleasant for living organisms.
Potential energy	It is stored energy.
Primary colour	A primary colour is one of there different colours of light red. Green and blue colours.
Prism	In optics, a triangular block of transport material (plastic glass, silica) commonly used to, bend’ a ray of light or split a beam into its special colours.
Projectile	A particle that travels with both horizontal and vertical motion in the Earth’s gravitational field.
Quantum mechanics	It is the part of physics that deals with radiation and the movement of atomic particles.
Rader	An acronym for radio direction and ranging device for locating objects in space, direction finding, and navigation by means of transmitted and reflected high-frequency radio waves.
Radiant heat	It is energy that is radiated by all warm or hot bodies.
Radiation	It is a kind of energy which is moving.
Radioactivity	It is the spontaneous alteration, or decay, of the nuclei of radioactive atoms, accompanied by the emission of radiation.
Radiocarbon dating	It is a method of dating organic materials (for example, bone or wood), used in archaeology.
Rainbow	It is an arch in the sky displaying the colours of the spectrum formed by the refraction and reflection of the Sun’s rays through rain of mist.
Reflection	The throwing back or deflection of waves, such as light or sound waves, when they hit a surface.
Refraction	It is the bending of waves of light, heat or sound when is passes from one medium to another.
Relativity theory	A theory that described matter, space and time and how they relate to each other.
Retine	It is the inner layer at the back of the vertebrate eye, which contains light-sensitive cells and nerve fibres.
Robot	It is a kind of machine that can do jobs without human help.
Rocket	It is a projectile driven by the reaction of gases produced by a fast-burning fuel.
Satellite	It is a kind of spacecraft.
Satellite dish	It is a kind of aerial.
Seismograph	It is an instruments that amplifies and record small movements of the ground caused by earthquakes or explosions.
Semiconductor	Crystalline material with an electrical conductivity between that of metals (good) and insulators (poor).
Sensor	It is a device that takes in and reacts to some kind of input energy and out puts a related electrical signal.
Shaft	It is a rod which rotates and is connected to the axis of a wheel or a gear.
Short circuit	It is the accidental or deliberate joining of two parts of an electric circuit by a conductor of less resistance that allows an excessive current to flow, usually blowing a fuse.
Silicon chip	It is a kind of crystal.
Siphon	It is a curved pipe or tube and is used to move liquids from one container to another.
Solder	It is an alloy and is used to join together wires and electronics components.
Sonar	It is a device which is fitted to ship and submarines and it is used to find objects under water.
Spectrometer	It is an instrument used to study the composition of light emitted by a source.
Speed of light	It is the speed at which light travels through emply space. Its value is 299,792, 458 metres per second.
Speed of sound	It is the speed at which sound travels through a medium, such as air on water. In air at a temperature of 0⁰c, the speed of sound is 331 metres per second.
Spark	A high energy discharge through a gas that lasts for a very short time, it is accompanied by a flash of light and a sharp crackling noise.
Solar energy	It is energy derived from the sun’s radiation.
Solstice	One of the two times of each year when the sun reaches its maximum northerly or southerly position among the stars. In the northern hemisphere, the summer solstice on June 21, is the longest day of the year and winter solstice on December 21 is the shortest day of the year.
Sound barrier	It is the point at which an aircraft attains the speed of sound.
Superconductor	It is a substance which has no electrical resistance.
Supersonic	It means faster that the speed of sound.
Telescope	It is a device for collecting and focusing light and other forms of electromagnetic radiation form distant objects.
Thermometer	It is a device used measures temperature of hotness.
Thermostat	It is a device used to keep the temperature in some place with in a set range.
Tide	It is the rise and fall of sea level due to the gravitational forces of the Moon and Sun.
Transformer	It is a device whose normal use is to transfer electrical energy with a change in voltage between input and output.
Transistor	It is a device for controlling the flow of minute electric current. It serves as a rectifier or as an amplifier of current.
Transponder	It is a transmitter cum-receiver which receive radio signals and retransmits them automatically often at a different frequency after amplification.
Troposphere	It is the lowest part, of the earth’s atmosphere in which most of the weather phenomena occur.
UFO	It is an unidentified Flying Object.
Ultrasonics	It is the study and application of the sound and vibration produced by ultrasonic pressure waves.
Uranium	Radioactive metallic element (system U) of proton number 92 and relatives atomic mass 238.029.
Vaporization	It is the change of state of a substance from liquid to vapour.
Velocity	It is the speed of an object in a given direction, or the rate of change of an object’s displacement.
VHF	It is very High frequency referring to radio waves that have very short wavelengths.
Viscosity	Resistance of fluids (liquids and gases) to flow. It is caused by friction between the fluid molecules moving against each other.
Voltage	It is the electrical pressure or potential difference measured in volts.
Voltmeter	It is an electrical instrument which measures voltage.
Vortex	It is intense circular or whirling motion of a fluid.
Warhead	It is the part of a missile, usually placed at the tip. containing a chemical explosive or incendiary charge and a mechanism for setting it off. It may also carry a nuclear device.
Water cycle	It is the continuous movement water between the ocean, atmosphere and the land. Water from the ocean evaporates by Sun’s heat and enters the atmosphere as water vapour. The water vapour condenses and comes down as rain from where it flows through streams and rivers into the ocean, thus completing the cycle.
Watt	It is the unit or power, the rate of energy transfer.